Baby’s Memory May Be Forming Earlier Than We Ever Thought

Surprising new research shows that babies display glimmers of consciousness and memory as soon as 5 months old!

In adults, the pattern of activity is as follows: your senses detect something and then activate the vision center of your brain — which causes a signal to travel from the back of the brain to the prefrontal cortex, holding the image long enough in your mind for you to notice it. Scientists can measure a spike in brain activity when your senses have picked something up, including a "late slow wave," which can be measured when the prefrontal cortex actually gets the message. Though it sounds like a detailed process, it only takes less than one-third of a second.

A team of researchers in France wondered if the same two-step pattern found in adults could be found in children. They monitored the brain activity in more than 240 infants' through caps fitted with electrode, but found that two-thirds of the children were too active for the movement-sensitive caps. The remaining 80 children in the study (ages 5 months, 12 months and 15 months) were then shon a picture of a face on a screen for a mere fraction of a second.

Cognitive neuroscientist Sid Kouider of CNRS in France watched for swings in electrical activity in event-related potentials (ERPs), in babies' brains. They found that an ERP similar to adult's could be found in babies 12 months old, though it was about three times slower than how quickly it would happen for adults. Most surprising, they noted, was the fact that 5-month-olds also showed a late slow wave (the arrival of the message to the prefrontal cortex), albeit was weaker and more drawn out than what they measured in the 12 to 15-month-old babies. The findings led Kouider to speculate that the late slow wave could be present in babies as early as 2-months-old.

The study, reported in Science, may indicate conscious thought. The late slow wave and feedback from the prefrontal cortex suggests that the image is stored briefly in baby's temporary "working memory." Consciousness, Kouider says, is made of working memory.

But the business of comparing brain waves in babies to adults is far more difficult than we'd think, says Charles Nelson, a neuropsychologist at Harvard Medical School in Boston who was not involved with the study. He said, "ERP components change dramatically over the first few years of life. I would be reluctant to attribute the same mental operation (i.e., consciousness) in infants as in adults simply because of similar patterns of brain activity." And Kouider agrees, saying, "The ERP components are not exactly the same as in adults," but admittedly so, the ERP signature found in the study on babies had all the same characteristics as those found in adults.

Still, Kouider and his team of researchers are intent to explore how these signals of consciousness connect to learning and language development. He said, "We make the assumption that babies are learning very quickly and that they're fully unconscious of what they learn. Maybe that's not true."